Electric arc furnace and the process of preparing castings



A ril 14, 1959 w. J. MULLANEY ETAL 2,831,489

ELECTRIC ARC FURNACE AND THE PROCESS OF PREPARING CASTINGS Filed Feb.17. 1956 s Sheets-Sheet 1 l I :i ii

0' Ln LIT-Jig 9 O 0 e E FIG. I

INVENITOR.

WILLIAM J. MULLANB GEOREE F. ALBRlGHT I WW April 1959 W. 'J. MULLANE'YET AL 2,881,489

ELECTRIC ARC FURNACE AND THEPROCESS OF PREPARING CASTINGS INVEN TOR.WILLIAM .1. MULLANEY GEORGE E ALRRIGHT United States Patent PatentedApr. 14, 1959 ELECTRIC ARC FURNACE AND THE PROCESS OF PREPARING CASTINGSWilliam J. Mullaney, Cleveland, and George F. Albright, East Cleveland,Ohio, assignors, by mesne assignments, to Otto N. Wanek, Bay Village,Ohio Application February 17, 1956, Serial No. 566,172

16 Claims. (Cl. 22-400) The present invention relates to electric arcvacuum furnaces and more particularly to a furnace in which castings maybe formed in any desired shape. It also relates to an improved processof preparing castings while a gas which is inert to or which issubstantially inert to the metal or mixture of metals being melted, ispassed through the furnace.

In preparing metals having comparatively high melting points, such astitanium, in electrical vacuum arc furnaces, it has been the practice tomake castings in cylindrical form. Castings prepared in such manner,however, must be reshaped prior to further processing. In accordancewith our invention, improved means are provided for producing castingswhich are angular in shape, such as square or rectangular, which may beprocessed without reshaping. In accordance with the invention, means arealso provided for continuously passing into and withdrawing from thefurnace while the metal is being melted a gas which is inert to themetal for cooling the furnace and removing impurities which arevolatilized during the melting operation. The invention is particularlyadapted for preparing castings from a metal which is in the form ofsmall or fine particles, such as powdered or pulverluent iron, chromium,tungsten, molybdenum or titanium. It is also possible by the in ventionto form alloys by utilizing a mixture of two or more powdered orpulverulent metals in such proportions that an alloy will be formed. Forinstance, by utilizing a mixture of powdered iron, powdered nickel andpowdered chromium in the desired proportions, such as approximately 18%chromium and 8% nickel, and the balance iron and minor impurities,alloys of the stainless steel type may be prepared or by utilizingpowdered nickel and powdered chromium in the proper proportions, such asapproximately 63% nickel and 22% chromium, and the balance powderediron, alloys of the Nichrome type may be prepared, or by utilizing theproper proportions of iron, chromium, molybdenum and the balancetitanium and minor impurities in which each of the metals is in a finelydivided state, a titanium base alloy containing approximately 2% iron,2% chromium, 2%

molybdenum, and minor impurities may be prepared. The furnace and themethod of the invention is also particularly adapted for the preparationof titanium castings of a square or rectangular shape and of acomparatively high degree of purity from sponge titanium in a finelydivided state and the construction and operation of the furnace will bedescribed in connection therewith although it will be understood thatthe invention is not to be limited thereto.

The invention will be better understood by reference to the accompanyingdrawings in which:

Fig. 1 is a side elevational view of the improved furnace, showing partsbroken away and parts in section;

Fig. 2 is an enlarged cross sectional view taken on a plane passingthrough the line 2-2 of Fig. 1, looking in the direction of the arrows;

Fig. 3 is a cross sectional view taken on a plane passing through theline 3-3 of Fig. 1, looking in the direction of the arrows;

Fig. 4 is an enlarged detail sectional view of the seal between thepiston rod and each end of the furnace;

Fig. 5 is a plan view of a slide movable in the feed hopper;

Fig. 6 is an enlarged vertical sectional view of the feeding columns andelectrodes, showing means for cooling the electrodes and feedingcolumns; and

Fig. 7 is a cross sectional view on a plane passing through the line 7-7of Fig. 6, looking in the direction of the arrows.

As shown more particularly in Figs. 1, 2 and 3 of the drawings, thefurnace is formed of a suitable metal 1 which is lined with a refractorymaterial 2 which will reduce radiation from the furnace to a minimum.The furnace is provided with a door 3 and may be supported on a suitablebase, not shown. Arranged within the furnace is a mold or crucible 4which is angular in shape and which is slidably mounted on a skid 5having spaced inner and outer walls 6 and 7. While the skid may besupported interiorly of the furnace in any desirable manner, as shownmore particularly in Figs. 1 and 2, a plurality of legs are providedwhich extend downwardly through the wall of the furnace and which aresealed therein by a suitable sealing material. As shown, a pair of legs8 extend downwardly from each corner at one end of the skid and a secondpair of legs 9 extend downwardly from each corner at the opposite end ofthe skid and if required, additional legs 10 may be provided whichextend downwardly from the central portion of the skid.

As shown in Fig. 1, the furnace is provided with a dome 11 having anupper substantially flat surface through which extends one or moreelectrodes 12 and also extending through the dome are a pair of feedpipes or columns 13 for each electrode. The lower end of each of thefeed columns and the lower end of each of the electrodes are maintainedin spaced relation to the bottom of the mold in any desirable manner. Asshown, the upper ends of the feed columns 13 are connected to a feedhopper 14 which may be maintained in the desired position by anysuitable mechanical means, such as a suitable hoist which may be rotatedin opposite directions to raise or lower the hopper by a reversiblemotor through reducing gearing, or a positioner mechanism may beprovided which may be operated electrically and since such mechanism isnow well known in the art, it has not been shown. The electrodes may besecured to and are movable vertically with the feed columns in a mannerto be subsequently described.

The number of feed columns and electrodes which are utilized may ofcourse be varied depending upon the size of the casting desired.Preferably, however, there "are two feed columns for each electrode. Asshown in Fig. 3 of the drawings, three pairs of feed columns areprovided and an electrode is arranged between each pair of feed columnsto form a series of rows and the lower end portions 15 and 15A of thefeed columns in one row are inclined in opposite directions toward theelectrode arranged between them and in a like manner, the lower endportions 15B and 15C of the feed columns in the second row and the lowerend portions 15D and 15E of the feed columns in the third row areinclined in opposite directions toward the respective electrode arrangedbetween them.

For feeding metal in small or fine particles to the feed columns, thehopper 14 is provided with a plurality of openings 16, each of whichopenings leads into a feed pipe 13 and a slide 17 is provided with aplurality of staggered openings 18 which are so arranged that powderedmetal is selectively fed through one of the feed columns to the mold.The finely divided metal may be fed to the mold by gravity which may beassisted, if desired, by mechanical or pneumatic means, and during thefeeding'of the metal into the mold, a current from a suitable source ofelectrical energy is passed through a terminal 19 and electrode 12 andarcs through the powdered metal passing from the outlet orifice ofthefeed column and thence through solidified metal in the mold to themold 4 and from the mold through a conductor 20 having one end securedto the mold and its other end in sliding electrical contact with a bar21. An outlet terminal 22 extends from bar 21 through the wall of thefurnace.

During the passage of current through the respective electrodes 12,means are provided for cooling the feed column through which finelydivided metal is being fed tothe mold, each of which cooling means isconnected to the feed column with which it is associated and is movablewith it. As shown more particularly in Figs. 6 and 7 of the drawings, apipe 23 surrounds each of the feed columns and is provided with upperand lower end connections 24 and 25 with the feed column, and

battles 26 are arranged between pipes 23 and feed column 13 and whilemetal is fed through each feed column, a cooling fluid, such as water,is passed from conduit 27 into the space between baifles 26 and the feedcolumn and is exhausted through a conduit means 28 on the opposite sidesof the baflies.

Means are also provided to cool the electrodes 12 through which currentis being passed and for this purpose, the lower end of each electrode isclosed and a pipe 29 having a lower open end is arranged within theelectrode and a cooling fluid, such as water, is passed into theelectrode through a pipe 30 and is exhausted through pipe 29 to conduitmeans 31. Electrode 12 is preferably of the nonconsuming type and may becomposed of tungsten or titanium provided with a tip 32 and to enablethe electrode to be raised with the hopper, a plurality of spaced bars33 are secured by suitable means, such as welding, to each electrode andto the respective pipes surrounding the aligned feed columns.

To enable the molten metal to be deposited uniformly in layers withinthe mold, means are provided for moving the mold in a horizontaldirection upon the skid. For this purpose, a pair of rams 34 and 35 areprovided, the ram 34 extending through one end of the furnace and ram 35extending through the opposite end of the furnace. Each of the ramsextends into a cylinder 36 and is provided with a piston 37 therein andthe rams are selectively moved in opposite directions by suitablehydraulic means well known in the art, thereby moving mold 4 alternatelyin opposite directions. Slide 17 is so arranged in hopper 14 that whenthe mold as shown in Fig. 3 of the drawings is moved toward the left,finely divided metal is fed through one of the feeding columns providedwith the inclined end portion 15A, 15C or 15E extending in one directiontoward its respective electrode whereas when the mold is being movedtoward the right, finely divided metal is fed through one of the feedcolumns 13 having inclined end portion 15, 15B or 15D extending towardits respective electrode. Valves for controlling the flow of the liquidin the hydraulic system may be actuated by limit switches in a mannerwell known in the art when each of the pistons 37 reaches the desiredposition in its cylinder 36.

After metal is deposited in the mold from the finely divided metal fedthrough each feed column on opposite sides of the electrode in the firstrow as shown in Fig. 3, finely divided metal may be fed alternatelythrough the two feed columns on the opposite sides of the electrode inthe second row, and finally, finely divided metal may be alternately fedthrough the feed columns in the third row during movement of the mold inopposite directions, to provide a uniform layer of metal in the mold, orif desiredjand particularly when the furnace is utilized in meltingmetals or alloys having a low melting point, such as iron or alloysthereof, the openings in the slide may be so arranged that finelydivided metal will be simultaneously fed to the three feed columns onone side of the row of electrodes while the mold is being moved in onedirection and will be simultaneously fed through the feed columnsarranged on the opposite side of the electrodes while the mold is beingmoved in the opposite direction. After the first layer of metal isdeposited in the mold, the hopper 14, together with the feed columns 13and the electrodes 12 may be raised and the process continued until acasting of the desired thickness is obtained.

The mold may be formed of any metal that will not contaminate the metalbeing cast. In forming castings of powdered titanium, it may forinstance be formed of copper or it may be formed of copper with a liningof titanium. During the melting process, means are provided for coolingthe mold. For this purpose, the mold is provided with spaced inner andouter walls 38 and 39 through which a cooling fluid, such as water, maybe passed in any suitable manner. As shown more particularly in Fig. 1of the drawings, the cooling fluid passes through an inlet pipe 40through a conduit 41 in ram 34 and through an aperture in the head 42 ofthe ram into the space between the walls of the mold and then flowsoutwardly through an aperture in the head 43 of ram 35 and conduit 44 inthe ram 35 to an outlet passage 45.

Means are also provided for cooling the skid 5 and for this purpose aninlet conduit means 46 is provided on one or more of the legs 8 throughwhich a cooling fluid, such as water, is passed, which cooling fluidflows between the walls of the skid and outwardly through a conduitmeans 46a in one or both of the legs 9 at the opposite end of the skid.If desired, however, the cooling fluid may be passed through conduits ineach of the legs at one end of the skid and after the cooling fluidflows between the walls of the skid, is passed outwardly throughconduits in each of the legs at the opposite end of the skid.

To prevent the metal which is being melted in the furnace from beingcontaminated by elements in the atmosphere, such as oxygen, nitrogen, orcarbon, means are provided for sealing the portion of the furnacethrough which rams 34 and 35 extend. For this purpose, a mercury seal isprovided in which the mercury is maintained under pressure between theouter wall 1 of the furnace and a cap 47, the inner periphery of whichis secured to the outer wall of the furnace by suitable means, such aswelding. As shown more particularly in Fig. 4, means including conduitmeans 48 and 48a which are connected to the inlet and outlet sides of apump, not shown, are provided for maintaining the mercury under pressurebetween the wall 1 of the furnace and the cap 47.

Means are also provided for first forming a vacuum within the furnaceand then continually passing a gas into and withdrawing it from thefurnace which gas is inert to the metal being melted for removing heatfrom the furnace and any volatile impurities which are formed during themelting operation. For this purpose, a pair of inlet conduit means 49and 50 are provided which are arranged below the dome of the furnace anda pair of outlet conduit means 51 and 52 are provided which are arrangedin the dome of the furnace. When the mold is first inserted into thefurnace and door 3 is closed, valves 53 and 54 in the gas inlet pipes 49and 50, respectively, are closed and the air within the furnace isWithdrawn through conduit means 51 and 52 which lead to vacuum pumps,forming a vacuum within the furnace. Valves 53 and 54 are then opened,the vacuum pump leading to conduit means 51 is shut off, and a gas whichis inert tothe metal being meltedis passed into the furnace throughconduit means 49 and 50 and is withdrawn through outlet conduit means52.

When sponge titanium in a powdered or pulverulent form is being meltedin the furnace, after a vacuum is first formed in the furnace, valves 53and 54 are opened and a gas which is inert to titanium, such as argon orhelium, is passed through conduit means 49 and 50 which becomescontaminated with impurities from the titanium and is withdrawn throughconduit means 52. The argon or helium which is withdrawn from thefurnace may then be passed through a scrubber and if desired may becooled and again passed into the furnace through conduit means 49 and50. It will be particularly noted that the outlet conduit means 52 islocated in the dome of the furnace and the hot inert gas is beingcontinuously withdrawn powdered or pulverulent sponge titanium is beingmelted because titanium is adversely affected by volatile impurities,such as oxygen, hydrogen, and carbon.

When it is desired to remove the casting from the furnace, door 3 whichis provided in one side wall of the furnace, is removed and tofacilitate the removal of the mold and casting, skid 5 is provided withindentations 55 into which a forked truck may be inserted to remove thecasting and mold from the furnace. A new mold may then be insertedthrough the door opening into the furnace and deposited upon the skid 5.The door which is provided with a suitable sealing material is thenreplaced and a vacuum is again formed in the furnace by removing the airthrough outlet conduit means 51 and 52. Valves 53 and 54 are then openedand an inert gas is continuously passed into and withdrawn from thefurnace during the melting operation in the manner previously described.

For ascertaining the temperature within the furnace, thermocouples 56and 57 extending into the furnace may be provided and if desiredsuitable peep holes which are closed by a suitable transparent materialmay also be formed in the wall of the furnace for observing the meltingoperation.

What is claimed is:

1. An electric arc furnace including a furnace wall, an angular shapedmold arranged within the furnace, a pair of feed columns extendingthrough the wall of said furnace and having outlet end portions arrangedin the mold at a spaced distance from the bottom thereof, an electrodehaving an end portion arranged in the mold between the outlet endportions of said feed columns, and the outlet end portion of one of saidfeed columns being inclined in one direction toward said electrode andthe outlet end portion of the other feed column being inclined in theopposite direction toward the electrode, means for alternately movingsaid mold in opposite directions, means whereby fine metallic particlesmay be fed into the feed column, the outlet end portion of which isinclined in one direction toward the electrode when said mold is movedin the same direction as the outlet end portion of the feed column isinclined toward the electrode and means whereby fine metal particles maybe fed into the other feed column when the mold is moved in the opposite direction, means for applying sufiicient electrical energy tosaid electrode to provide an arc of suflicient intensity between theelectrode and the metal particles passing into the mold to melt themetal particles, and means for cooling the mold, the electrode, and thefeed columns during the melting operation.

2. An electric arc furnace including a wall, a mold arranged within thefurnace having a bottom wall, a hopper for metal particles arrangedabove said furnace and having a pair of feed columns arranged in spacedrelation to each other and extending downwardly through the wall of saidfurnace, said feed columns having their upper ends connected to saidfeed hopper and their lower end portions arranged within said mold andin spaced relation to the bottom wall thereof, an electrode extendingthrough the wall of said furnace and having its lower end portionarranged between said feed columns, means arranged above the mold forconnecting said electrode to said feed columns, means for moving saidmold in opposite directions relative to said feed columns, means wherebymetal particles may be fed into one of said feed columns when the moldis moved in one direction and means whereby metal particles may be fedto the mold through the other feed column when the mold is moved in theopposite direction, means for applying sufficient electrical energy tosaid electrode to provide an arc of sufficient intensity between theelectrodes and the metal particles which are fed into the mold to meltthe metal particles, means for cooling said mold, electrode, and feedcolumns during the melting operation, and said hopper, feed columns, andelectrode being movable vertically relative to the bottom of the mold sothat after a layer of metal is formed in the mold, additional layers ofmetal may be deposited in the mold to form a casting of the desiredthickness.

3. An electric arc furnace including a wall, a mold arranged within thefurnace having a bottom wall, a hopper for metal particles arrangedabove said furnace and having a pair of feed columns arranged in spacedrelation to each other and extending downwardly through the wall of saidfurnace, said feed columns having their upper ends connected to saidhopper and their lower end portions arranged within said mold in spacedrelation to the bottom wall thereof, an electrode extending through thewall of said furnace between the two feed columns and having its freeend portion extending into said mold and the lower end portions of eachof said feed columns being inclined toward said electrode, means formoving said mold in opposite directions relative to said feed columnsand electrodes, means whereby metal in the form of fine particles may befed to one of said feed columns when the mold is moved in the samedirection as the lower end portion of the feed column is inclined towardthe electrode and means whereby fine metal particles may be fed into theother feed column when the mold is moved in the opposite direction,means for applying sufficient electrical energy to said electrode toprovide an arc of sufficient intensity between the electrode and themetal particles which are fed into the mold to melt the metal, means forconnecting said electrode to the feed columns, and said hopper, feedcolumns, and molds being movable vertically upwardly after each layer ofmetal is deposited in the mold to provide a casting of the desiredthickness.

4. An electric arc furnace including a wall, a rectangular-shaped moldarranged within the furnace having a bottom wall, a hopper for metalparticles arranged above the furnace and having a series of feed columnsarranged in pairs in spaced relation to each other and extendingdownwardly through the wall of said furnace, each of said feed columnshaving its upper end connected to the hopper and its lower end portionarranged within said mold in spaced relation to the bottom wall thereof,a plurality of electrodes, each of which is arranged between each pairof feed columns to provide a series of rows consisting of two feedcolumns and one electrode and the lower end portion of each feed columnin each row being inclined toward the electrode arranged therebetween,means for moving said mold in opposite directions relative to said feedcolumns and electrodes, means whereby metal in the form of fineparticles may be fed into at least one of said feed columns which isinclined in one direction toward said electrode when the mold is movedin the same direction as the lower end portion of the feed col umn isinclined and means whereby fine metal particles may be fed into at leastone of the feed columns on the opposite side of said electrodes when themold is moved in the opposite direction, means for applying sufiicientelectrical energy to the electrode which is arranged ad- 7 jacent acolumn through which metal particles is being fed to provide an arc ofsufiicient intensity between the electrode and the metal particles tomelt the metal, means for connecting said electrodes to the feedcolumns, and said hopper, feed columns and electrodes being movablevertically upwardly after each layer of metal is formed in the mold toprovide a casting of the desired thickness.

5. Apparatus as defined in claim 4 in which means are provided forselectively feeding metal in the form of fine particles to one of thefeed columns which is inclined in one direction toward one of theelectrodes when the mold is moved in the same direction as the lower endportion of the feed column is inclined and for selectively feeding metalin the form of fine particles to the other feed columns arranged on theopposite side of the electrode when the mold is moved in the oppositedirection and for selectively and alternately feeding metal particles tothe feed columns on the opposite side of each of the other electrodeswhile the mold is moved in correspondingly opposite directions and inwhich means are provided for selectively applying suflicient electricalenergy to each electrode to provide an arc of sufiicient intensitybetween each electrode and the metal particles passing in proximitythereto to melt the metal.

6. An electric arc furnace including an outer wall, an angularly-shapedmold arranged within the furnace in sufiiciently spaced relation to thefurnace wall to permit substantial horizontal movement of the moldwithin the furnace, said mold including a flat bottom wall and sidewalls extending upwardly from the bottom wall which side walls providewith the bottom wall an angularlyshaped casting cavity for receivingmolten metal, means for providing a passageway through which metal inthe form of small particles may be fed into a portion of the cavity ofthe mold, an electrode, said electrode having its inner end portionextending into the cavity of the mold in spaced relation to the bottomof the mold and in close proximity to the metal particles passing intothe mold, means for applying sufiicient electrical energy to saidelectrode to provide an arc of suflicient intensity between theelectrode and the metal particles passing into the cavity of the mold tomelt the metal particles, means for alternately moving the mold inopposite directions in a horizontal path relative to the electrode andthe metal particles while the metal particles are being passed into thecavity of the mold so that during the melting of the metal particles auniform layer of metal will be deposited upon the bottom wall of themold and will be retained in place by the side walls of the mold, andmeans for cooling said mold during the melting operation to form anangularly-shaped flat casting within the mold cavity.

7. A substantially closed electric arc furnace including an outer wall,an angularly-shaped mold arranged within the furnace in spaced relationto the furnace wall, said mold being provided with a flat bottom walland side walls shaped to provide with the bottom wall anangularly-shaped casting cavity for receiving molten metal, meansextending through the wall of the furnace and terminating Within thecavity of the mold for providing a passageway through which metal in theform of small particles may be fed into a portion of the cavity of themold, an electrode having its free end portion arranged in the cavity ofthe mold in spaced relation to the bottom wall of the mold and in closeproximity to the metal particles passing into the mold, means forapplying sufiicient electrical energy to said electrode to provide anarc of sufiicient intensity between the electrode and the metalparticles passing into the cavity of the mold to melt the metalparticles, means for alternately moving the mold in opposite directionsin a horizontal path relative to the electrode and the metal particlespassing into the mold cavity during the melting of the metal particlesfor providing a uniform deposit of metal within the cavity of said moldwhich metal is retained in place by the side wall means of said mold,means for cooling said mold during the melting operation to solidify themolten metal deposited in the mold cavity in the form of a flat casting,and means during the melting and casting of the metal particles forcontinually passing a gas through the furnace which is inert to themetal being liquefied and cast to cool the furnace and to remove fromthe interior of the furnace impurities from the metal which becomevolatile during the melting and casting of the metal particles.

8. A substantially closed electric arc furnace including a bottom wall,side walls extending upwardly in a substantially vertical direction fromthe bottom wall of the furnace to provide a lower chamber and said sidewalls being then extended upwardly and inwardly and merging at theirupper portions to provide a dome for said furnace and an upper chamberwhich is in communication with but is substantially smaller than thelower chamber, an angularly-shaped mold arranged within the lowerchamber of said furnace which mold is in sufficiently spaced relation tothe furnace wall to permit substantial horizontal movement of the moldwithin the furnace, said mold having a flat bottom wall and side wallsextending upwardly from its bottom wall to provide a casting cavity,means extending through a wall of said furnace and terminating in thecavity of said mold for providing a passageway through which metal inthe form of small particles may be fed into a portion of the cavity ofsaid mold, an electrode, said electrode having its inner end portionextending into the cavity of said mold and being arranged in proximityto the metal particles passing into the cavity of the mold, means forapplying sufficient electrical energy to said electrode to provide anarc of sufficient intensity between the electrode and the metalparticles passing into the cavity of the mold to melt the metalparticles, means for alternately moving the mold in opposite directionsin a substantially horizontal path relative to the electrode and themetal particles passing into the mold while the metal particles arebeing melted to provide a substantially uniform deposit of metal in thecavity of said mold, means for cooling the mold during the meltingoperation to solidify the molten metal which is formed into asubstantially flat casting, inlet means extending through the wall ofthe lower portion of the furnace through which a gas which is inert tothe metal being melted and cast may be passed into the lower chamber ofsaid furnace and outlet means extending through the wall of the domeportion of the furnace through which the inert gas may be withdrawn forcooling the furnace and removing there from volatile impurities from themetal particles which volatile impurities are formed during the meltingoperation.

9. An electric arc furnace comprising side and end walls and an upperwall arranged to provide a substantially enclosed chamber, arectangularly-shaped mold arranged within the chamber of said furnacewhich is spaced at a sufiicient distance from the walls of said furnaceto permit substantial longitudinal movement of the mold within thefurnace, said mold having a bottom wall and upwardly extending side andend walls to provide a rectangularlyshaped casting cavity, a feedingcolumn extending through a wall of said furnace and having its free endportion terminating within the cavity of said mold through which metalin the form of small particles may be fed into the cavity of the mold,an electrode having its free end portion extending into the cavity ofsaid mold in proximity to the metal particles passing into the cavity ofthe mold, means for applying suflicient electrical energy to saidelectrode to provide an arc of sufficient intensity between theelectrode and the metal particles passing into the cavity of the mold tomelt the metal particles, said mold being of sufficient length that itsend walls are spaced a substantial distance from said electrode and saidfeeding column when the mold is in a substantially central positionwithin said furnace, means for alternately moving said mold in oppositedirections in said furnace while the metal particles are being melted sothat a uniform deposit 2,as1,4se

of metal will be formed within the cavity of the mold, and means forcooling said mold to provide a rectangularly-shaped casting within thecavity of the mold.

10. A substantially closed electric arc furnace including spaced endwalls, a stationary skid arranged within said furnace, anangularly-shaped mold arranged within the chamber of said furnace, saidmold having a bottom wall slidably mounted on said skid and side and endwalls extending upwardly from its bottom wall to provide anangularly-shaped casting cavity, a feeding column extending through saidfurnace and having its free end portion terminating within the cavity ofsaid mold through which metal in the form of small particles may be fedinto the cavity of the mold, an electrode having its free end portionextendin into the cavity of said mold in proximity to the metalparticles passing into the cavity of said mold, means for applyingsufficient electrical energy to said electrode to provide an arc ofsufficient intensity between the electrode and the metal particlespassing into the cavity of the mold to melt the metal particles, saidmold being of suflicient length that its end walls are spaced asubstantial distance from said electrode and feeding column when themold is in a substantially central position between the end walls ofsaid furnace, means for alternately moving said mold in oppositedirections on said skid while the metal particles are being melted sothat a uniform deposit of metal will be formed in the cavity of themold, and means for cooling said mold to provide a rectangularly shapedcasting within the cavity of the mold.

11. A substantially closed electric arc furnace includ ing spaced endand side walls, a rectangularly shaped sta tionary skid arranged in saidfurnace, and one of the side walls of said furnace being provided with adoor arranged opposite to said skid, an angularly-shaped mold arrangedwithin said furnace, said mold having a bottom wall slidably mounted onsaid skid and side and end walls extending upwardly from its bottom wallto provide an angularly-shaped casting cavity, a feeding columnextending through one of the walls of said furnace and having its freeend portion terminating within the cavity of said mold through whichmetal in the form of small particles may be fed into the cavity of themold, an electrode having its free end portion extending into the cavityof said mold in proximity to the metal particles passing into the cavityof the mold, means for applying sufficient electrical energy to saidelectrode to provide an arc of sufiicient intensity between theelectrode and the metal particles passing into the cavity of the mold tomelt the metal particles, said mold being of sufficient length that itsend walls are spaced a substantial distance from said electrode andfeeding column when the mold is in a substantially central positionbetween the end walls of said furnace, means for alternately moving saidmold in opposite directions on said skid while the metal particles arebeing melted so that a uniform deposit of metal will be formed in thecavity of the mold, and means for cooling said mold to provide arectangularly-shaped casting within the cavity of the mold, and saidskid being provided with indentations below said mold for receiving aforked truck by means of which the mold may be removed from said skidand furnace and a new mold deposited on the skid when the furnace dooris open.

12. The method of preparing angularly-shaped flat castings whichcomprises inserting within the walls of a substantially closed furnaceand in spaced relation to the walls of the furnace a mold having a fiatbottom wall and an angularly-shaped casting cavity, feeding metal in theform of small particles into one portion of the cavity of the mold,applying sufiicient electrical energy to an electrode having a free endportion aranged in the cavity of the mold in proximity to the metalparticles being fed into the cavity of the mold to melt the metalparticles, alternately moving said mold in a horizontal path in oppositedirections relative to said electrode and the metal particles being fedinto the cavity of the mold to provide a uniform deposit of metal withinthe cavity of the mold, and cooling the mold to solidify the metalformed therein into an angularly-shaped flat casting.

13. The method as defined in claim 12 including the step of passingthrough the furnace a gas which is inert to the metal being melted tocool the furnace and to remove from the furnace impurities in the metalparticles which volatilize while the particles are being melted.

14. The method as defined in claim 13 in which the st. all particleswhich are fed into the cavity of the mold consist essentially oftitanium and minor impurities.

15. The method of simultaneously preparing an alloy and casting it intothe form of an angularly-shaped casting which comprises inserting withina substantially closed furnace in spaced relation to the walls thereof,a mold having a flat bottom wall and an angularly-shaped casting cavity,feeding into a portion of the mold cavity at least two metals in theform of small particles in such proportions relative to each other thanan alloy will be formed when the metals are mixed together in the moltenstate, applying sufficient electrical energy to an electrode having afree end portion arranged in the cavity of the mold in close proximityto the metal particles being fed into the mold to melt the metalparticles, alternately moving said mold in a horizontal path in oppositedirections relative to said electrode and the metal particles being fedinto the cavity of the mold during the melting operation to form auniform layer of metal within the angularly-shaped cavity of the mold,and cooling the mold to solidify the metal deposited therein to form aflat angularly-shaped casting.

16. The method of simultaneously preparing a titanium base alloy andcasting it into the form of an angularly-shaped hat casting whichcomprises inserting within and in spaced relation to the walls of asubstantially closed furnace, a mold having a fiat bottom wall and anangularly-shaped casting cavity, feeding into a portion of the cavity orthe mold a mixture comprising a predominant amount of titanium in theform of small particles and a minor amount of at least another metal inthe form of small particles in such relative proportion to the titaniumparticles that it will form an alloy with the titanium when the metalsare mixed together in the molten state, applying sufficient electricalenergy to an electrode having a tree end portion arranged in the cavityof the mold in proximity to the mixture of metal particles being fedinto the cavity of the mold to melt the metal particles, alternatelymoving said mold in opposite directions in a horizontal path relative tosaid electrode and the mixture of metal particles being fed into thecavity of the mold to provide a uniform deposit of the molten metalwithin the angularly-shaped cavity of the mold, passing through thefurnace during the melting operation a gas which is inert to the metalparticles being melted to cool the furnace and to remove from thefurnace volatile impurities from the mixture of metal particles whilethey are being melted within the cavity of the mold, and cooling themold to solidify the metal deposited therein into an angularlyshapedflat casting.

References Cited in the file of this patent UNITED STATES PATENTS575,829

OTHER REFERENCES Induction Melting and Casting of Titanium Alloys, by P.H. Brace, Metal Progress, February 1949, pages 196-400.

16. THE METHOD OF SIMULTANEOUSLY PREPARING A TITANIUM BASE ALLOY ANDCASTING IT INTO THE FORM OF AN ANGULARLY-SHAPED FLAT CASTING WHICHCOMPRISES INSERTING WITHIN AND IN SPACED RELATION TO THE WALLS OF ASUBSTANTIALLY CLOSED FURNACE, A MOLD HAVING A FLAT BOTTOM WALL AND ANANGULARLY-SHAPED CASTING CAVITY, FEEDING INTO A PORTION OF THE CAVITY OFTHE MOLD A MIXTURE COMPRISING A PREDOMINANT AMOUNT OF TITANIUM IN THEFORM OF SMALL PARTICLES AND A MINOR AMOUNT OF AT LEAST ANOTHER METAL INTHE FORM OF SMALL PARTICLES IN SUCH RELATIVE PROPORTION TO THE TITANIUMPARTICLES THAT IT WILL FORM AN ALLOY WITH THE TITANIUM WHEN THE METALSARE MIXED TOGETHER THE MOLTEN STATE, APPLYING SUFFICIENT ELECTRICALENERGY TO AN ELECTRODE HAVING A FREE END PORTION ARRANGED IN THE CAVITYOF THE MOLD IN PROXIMITY TO THE MIXTURE OF METAL PARTICLES BEING FEDINTO THE CAVITY OF THE MOLD TO MELT THE METAL PARTICLES, ALTERNATELYMOVING SAID MOLD IN OPPOSITE DIRECTIONS IN A HORIZONTAL PATH RELATIVE TOSAID ELECTRODE AND THE MIXTURE OF METAL PARTICLES BEING FED INTO THECAVITY OF THE MOLD TO PROVIDE A UNIFORM DEPOSIT OF THE MOLTEN METALWITHIN THE ANGULARLY-SHAPED CAVITY OF THE MOLD, PASSING THROUGH THEFURNACE DURING THE MELTING OPERATION A GAS WHICH IS INERT TO THE METALPARTICLES BEING MELTED TO COOL THE FURNACE AND TO REMOVE FROM THEFURNACE VOLATILE IMPURITIES FROM THE MIXTURE OF METAL PARTICLES WHILETHEY ARE BEING MELTED WITHIN THE CAVITY OF THE MOLD, AND COOLING THEMOLD TO SOLIDIFY THE METAL DEPOSITED THEREIN INTO AN ANGULARLY-SHAPEDFLAT CASTING.